SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48936dc2b28957b64054f756c4ddcfd6f32f5372e43dcbb0bd6ce3d004c92d0' 
  AND token = 'xq1BMEnv2Z4m0tUPrmLc1C60OyCVDPi+oFtKLJgt+Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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