SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05097916761043e556f32be1270b0e672fade2a67b2eb0875e7952e044736dfc' 
  AND token = 'Rv9R2whU5B4ej9/ojK5GwiZKOmkWbNw9Ed0n/o8BToM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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