SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2ae83859b944a87eabe074c87c8a2cc1f79a159623566b4158dda3122f24f9' 
  AND token = 'GGxC2GcBCgHRcB2sYETkxrbalNYN7NssudC5ggQIsBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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