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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0961a5da886f9c880be7b69475e0881439ac2b3cc50a6ddab3221c92075ba09' 
  AND token = 'Z18D/Dgy2Xnfycf6ImnY3LhoNQuh9ZaUlO2KxsqGnpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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