SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb406a32d76c3278759feceb714273eda8e48e73a731e25feddf9ca7a59b291a' 
  AND token = 'wtPI/tBj6yZMgM5/8Qx4BnfIChpjOqOzGS+gMQxZZVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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