SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03bba6cf338e04678ef1c108f735eeba42f9d619a6f9856323e2fdb83db17e3a' 
  AND token = 'KUvYAAEsNPxOWo7+IauWaWAAU/nqH+7tozjinKnrj1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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