SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4c0344246b6009949bba361f878cd9bc5c46de9c9cf2d133d1bf8eefcf99c442' 
  AND token = '91LbiHllfM+xPLs45BpiNknMl3S3yanbMmURPoxvNnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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