SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdf9c295296b1fd3fb1137573eb5c5aa6a8b3fcebbfac992ca9111cc8dd84830' 
  AND token = 'aXZadZkNhXXEZCzMT2nrY3KIJ1mm+6dFMVJgfMqM9fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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