SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe521dd46cd5cae1c20449c0585bffa476e9503cd0dedca093ccfd711b0b7ce' 
  AND token = 'h3E1DIWlZkCbzrfMQoS5cr9pCOrttcDcw3xQpq7nlno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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