SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b66af5e1636d0997f96210843808f7f8e2c6920a1dca2707f4c6e2ea3475b544' 
  AND token = 'Gs0XYEx4IFddgJwDu6sBBvZoKDgXvUH+lV9BqopAXqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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