SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '538ecc7e0e3333ce974140a00797365757933b8c8852fb0c1e89f3bc731c0ad7' 
  AND token = 'QxwJasvZmEZYLT6u6xfhGRvJLx9jygj5xnCH7V4uxyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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