SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6fa57bccf08a5e4e622e60a7149b512fffb7fb371cefbc0b3a29043303aed05e' 
  AND token = 'jz3mSosuKd9XvWyHUl8yPZxPxd5UogS5Kj+zw3g5YnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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