SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae68838004da0a90452ca470bbb21b906b826336e522b6a9f5b8e65ccf36f9f4' 
  AND token = 'p51tgBSFFAOJJjN/eEFQMHtjrCJma2UjBkCP99OogZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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