SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '776a4f451809a87390c508828490a7a6150febd6507d53702ba16fdb4cbf35c6' 
  AND token = 'Wlr52majVFRVDHwY5b7zmolIMn/VEmwfOEzAaSmITAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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