SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4131fd296db9c3711d4189ad0f3224450158cfb0076cbcc7e7055a20935d1d3e' 
  AND token = '2xTKhcoEonL/ihNqvzneuxJpJtCjLfbWl6N/etokDiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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