SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '597379ab217f4e818cb4e07ac4c6207a1f43f607a65e91d4c46477cd152338d4' 
  AND token = 'kSGjBHDvlcG/mlKVCWD5wqBeXFqfLtfTT6kD01Qgi4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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