SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '231cc238c8f04b31ec7c02fb36b510f89442c1f33737fec125424b65db09ab03' 
  AND token = 'C+Y+tTXyF80m/Whaw0IH8CCiwsmRKXEgpHLksqlVLwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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