SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '383a4f81ab5432258a1a15ef152cd07cecb67f0edff6153493091214c7f4ecfc' 
  AND token = 'qqFFZ063upaKxxAGRC2jvfKvD72rbjLn15LChnSRgt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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