SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d5dbcb4b196c101dad83fca86543323c728799a0b6a478236327fa2043f0f72' 
  AND token = 'LIE5V7CMGx7JLB7V1Ae3HbuTUJJ/G0XscKroqP/njhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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