SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2174f3da4dae423f0768150383007073da8bfdb96ff597a0d938f09d61782753' 
  AND token = 'CUzaoLlyvXJezV+jO8OwMRtxym9CHvo8lXH/1YzO34U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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