SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '336dc0fd44927ef6a85d6e8916aa6cd78d4522f7679073fe3744e5b1b8294604' 
  AND token = 'gi2JdWdObQROKghOqU7yIraJo2/r6O+zMpa6tszvDyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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