SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3125fefbb3a372b2b39d469a4abc97720b789821fff5641025097d3160a9bad1' 
  AND token = 'aP1uEIoayXzMt18zC0MlnL6TWte4MZFt/a/fHgOVZaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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