SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78fa38c2f5bd4f4f752157ed16a77e0a61d19d4467f9e9341bff45cf7745ef38' 
  AND token = 'AzqC0JdAYTrvMKUpAjCDSB2aNHnGIwad16PAZuVGr0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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