SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ef7647cd3e9871cd98a4c93fbfaf89f144d8a3c5b4364866d31b567367d9c49' 
  AND token = 'zHhIGce6IUvadxoamjTNO/jXHUJ4wPiQgevKgWjhwSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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