SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c8ccef33a5c8b5ccbee9135b457ce12cf15cd8b260d7f558ef94f75c7a9cab3' 
  AND token = 'AMpAneRsfK2VFiBSdGcOhEA+r9cEDrMkpHN0oY3J0zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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