SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c78f298bd49f389b010093059460f432ea24b764d2072969fe9f6bf46700b569' 
  AND token = 'tpqwbGW7MP+yqmv0vuEYNu4N6+LtQFE8lX88stsozFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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