SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de0776caa9c5778371eac7853108da882cf1bc4074694d44c51b2e23a8650466' 
  AND token = 'hryEzerLmkNBNrQY2cisiBgn/S6SGYqtR0ow6psbdD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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