SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85f1b60591c638228e9e91f50273145c0647bce58af4d2473e9da37f7adaf3f6' 
  AND token = 'B4Fb3U90Q5OpOh6mnTginwobWl38AFGZ7GspD9NmP30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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