SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71c7cc2f65571ea208309f976f44234de1421849f8abc4e0dbf0f3f491dea341' 
  AND token = 'KachPl5K/IhMF2/qpEMcKpjjGuT42AIB9QNd7WCp/JQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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