SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce3ec40b12627a62891f72878561d483d3ad1e954a5565690984baf811f536d3' 
  AND token = 'uBuMy4wiQ8FG0r3H51ETuTj7VcsBWREXx1wYzWpcXvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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