SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50ef64cf8a32cc0d1c179b484aae3f84272dd5a4f1db7c5fb67962532dd94645' 
  AND token = 'Ggtjm6+FhBZvtt0swrT0bZ8a1/8zVuyYK3zHauK5X7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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