SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd41e7bdd098bc9875496c1ce4e70271770a0362d563a8c666f85be208d2edb1' 
  AND token = 'FrfLFDVdxHI2YBKUUEJhAKICi8rjrMtThGISbfdVDc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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