SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db68fba54bb2c97e30dd196a51067d45c112807436a67574f1cfe04da2ef4f00' 
  AND token = '/WUKNoZXtxbY2ZM2xBMP1HhEa4qlx9aiPPqTy4zX8sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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