SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db3e2aeaec5da329124e6bef05d37202007a953be05cb9cccf7e453430fc528f' 
  AND token = 'vJPgTjihZLgd7Bo323d2pFUYACMtYOFAejO4g/jL0kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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