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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7b0d3000e378b4cb6f8819601f7c74d936c7734aea05298efa5cca2879e4ee4' 
  AND token = '9aOJ0sWMp0gzCO4wdKDNtqsbs7VFYOD8+ZGmwL+JHzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}