SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f957513721f47a735396ec1c4d90313ce131720886e65b81537648134aff2e57' 
  AND token = 'yoeLxMwAFyuXQg/VCTij3/CFs8evUOlsKbUN1xNC0wU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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