SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cbd5e86faa99f55291a28309d7c7da619c15b2fcb9d7bee4c51e77fe43076af' 
  AND token = 'lkqvZWMAQvz3rwI/KE1QsXpjzP6gV1mv1RAC8xIXaF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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