SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '694592ada98117e3cfa508be40b098ece8550339bdb2b320f6348a045c1b5c85' 
  AND token = 'b99ot03bBGoI0miK5SnjgPnJyCT9OKzRmhl8qvC/eok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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