SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91463c780f68045e73e5600047070a2c91742b0fc019ca3a51e4500fcfc3871' 
  AND token = 'qVL3lkdpBdYSUD4dqlzcZMtj9sCwiwh2kFHO/HAPB4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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