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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc9d80e77e0afd237e9e0ba6b1ee9f25469e12c3777e603486aba2294feb3396' 
  AND token = 'NXsBcLP6ouXtZ2vF4NGPmJ4JRBj8Xio3xBR0zoyPXgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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