SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7554386f13bf40285ed790c562d857cc85c89bd9d7687c6bf71f2469259b857f' 
  AND token = 'kVZNytWixS+ASWKVbqIwxPSe6YS2/MESfhoPCiLG3nM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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