SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f0a058f9f3e9783c56209d1f7c55efa71b445c675b876ad98262a87b7c1af9' 
  AND token = '+cL+s4oN7pVWOF3YFkTwkWKdL7HaJW4Pc8Mgt/PvChs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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