SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d467d5d09f247dbfe0908390dfd40655c235b51358bdb707b8711889236ba4' 
  AND token = 'ksmtlD1snCvrm7RfcHFkg+RBR6nfFIem989B4vd5zog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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