SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99992686994036be3e32ac7fbfcf2ba85865b68b78855ca00a056a5640a688f5' 
  AND token = 'hx8Kf0wnYKtGkM0fnfDmxgBiZUHbchgmMiDuK8whGdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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