SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8615bd95785064ffafca92b4202a2c947cd9cd7233a686a5e977a14c9c82c747' 
  AND token = 'bO/UZzVOi4gsv3Y5xQZGOfA2QqapTZZ0IlH9SlL5Yh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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