SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd9da3afa4e4a5442652db9e570a29ff40c807b4e1997af127229d717b9e3bea' 
  AND token = 'oUqs8P08RaxlcAafRWykZAdCL8yHpYyeWt3GqsbeMqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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