SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c6e17214ac677665f4ca4e6017d42757ea5fd890660dcf2498ddf4aa2803042' 
  AND token = 'dG0jPPifX7b9tzAf92NmyWQvz2MULrurkZXs9crxrwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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