SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d5609c723650e2e1c6d109440fc5443edea423518bf2732d5a868ebbae0600' 
  AND token = 'AF51ItFzOOiH21ZPV7PGN5wPjhOnYYr2NiWtBrFNNO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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