SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778a8dbb8366006e0902794054ce268eb1619e736e624a4636bac20c06a54604' 
  AND token = 'jTYcSDLfMuIhW9j5pIcTub7xbyva3DtP71TWTCTfxCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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