SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab74006c831d058b468cd764a7c386fb0cf0f9516e04fbdef3caebaff830d032' 
  AND token = 'yFbZnuGdSdcS6WBtMmVlOj3KSNI4+jVzB0DPGdfEm4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}