SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '911aecd6309d7df6421015127d0c1d4cd2a906920dae3788eb67c6250c31eedb' 
  AND token = 'VYILAftPs+Rm0ga2hYbibqVzM/A6EQDghOsk710+39g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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