SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c3c0bc9e7f7526233fd5af014e8baeffc57a2ea93a7a07bddafcc70d0260473' 
  AND token = 'Q6eZSH5h8HkzT4xousWkg2WDF6h3ynnU/HeEOhOYbLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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