SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55371de2629eb014baa26c101f9db7981b89bd86907a6cb33e2bf8d84f0cded6' 
  AND token = 'YA8OJ2CGMuHTqNJWwsCL4UivbF2XRLqNFZ/X5RnYZ+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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