SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987c74a4f87ed863a8974555cce56263cca65150e5189dd3e2b9c41d14dc9c0e' 
  AND token = '6XzEy3V+9WKvN9ujMvKigPHBjTYwvMaaZtkznFjhN5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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