SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8ee7e1e7fe5caec48d7db3dee4f139e172234498e63380ad2aee113630e5962' 
  AND token = 'cguyoS6BNljCmwgvk/3MPQ3OZnPBAj7FbWjcQnnKRA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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