SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e13dbba0b820af1426d8f3900857ae27a8b7c61f73159edecd1a17c8fd4ce2' 
  AND token = 'P0q2R/ea+DZIHH0Mt/cXKjdKE/bGo72ch9TQOn/ElXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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