SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8eddb200cb1cfd7508f2fdd99e0e6d1212d8090db51402aeff67ece24c4e5798' 
  AND token = 'Z+nxowFwKJMiJrBg8UK02wfxKdBDM7LwW1mARMitpfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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