SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab1aaab6230d402983ae638df9f87c5e82b544ea1c4e43f8815cc02db84602f' 
  AND token = 'EEJSpHOWVDWcifEOIYU6n5Y+0dDzwPhaYBtHM0dOE4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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