SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1df7839731a7c74f805996888972e2cc22392c7405913108719303b64ac2441a' 
  AND token = 'H8hABDQ9e5/65wxe8YEwRQaoAfDegwfozh3+uw9W7UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}