SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41c35d21f206712c9b304641bd95c90774f95ddc3394324d58f1aaba53d9edb1' 
  AND token = '3OHtt/CGVKszpZYUf+rJxQhFug2h7tMSqxKeNSSGRfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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