SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54643c6d1e1bf8bf497b8a2a5287014b8276b4b30669bcfc75193cd3d195a86e' 
  AND token = 'QtAnSDQM6vyHetYxM+IAxrQHAnhqhvEpvXT/TaC8lwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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