SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4153ce2349c9aca4577f4cd9a577f3abe593ba6fec17d6b788f97a71bcf7ccc' 
  AND token = 'sct3/ebd+lm4anMUEjT3zQlcI84AoHJy9xv8lTMFHMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}