SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1755fb9273f073ceba2f81e4c0dce5f796ba2452882618c844c2712c85d4253' 
  AND token = 'o3k3BO4/77R6dHv7KCepxU1IBvwrK3eQzalOJ8wHqKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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