SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '593a80eb931a44f483382ddcf08bb3f0c28aa8de956ba446c589a364f5f4754f' 
  AND token = 'Q8y7K3GKXWiDNAQuKnPfQ6P30poj2cNvZEGNDvqbAHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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