SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30c568f8f106497a9e521027424ad98f0a6f120b668caeeb01abee316fff9347' 
  AND token = 'Arx7HqJbqGNf8VamPkMf6fztEaSFUivIfe17V8f4U3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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