SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286f22b14cb7c83ae1745b6969b9a49acc4d5e1be03a9a693cc9f15bc24a4b5d' 
  AND token = '4CPpwNtQ4mU3xAczQp2D+nUAIyVD2diD7/Yuj3d4C34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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