SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e994efc3c87c033f26884310eb815703665a63696a696ff6b1644a9121499b79' 
  AND token = 'Sjn2euv85tUYlgPteB6ZSwHz0CuhGgsiJ+O8ROFAkA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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