SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a9ffdc117adf24b38c56510454d100c99425e17027516cc925eeea9b35074f1' 
  AND token = 'kHhRb+z6jZObOhiE8hBSGMwviC2F6W/l7uo/gdUmLlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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