SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0743f32d143f3b9f4b3dc4a8c3a21acefe0602011f41bb825d16af806af94ee2' 
  AND token = 'f8ZiGRMrelIeua+LEFFFp7nfh5j46CTPOyK0MMl2scE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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